Bulk ruthenium chemical mechanical polishing composition

ABSTRACT

The compositions of the present disclosure polish surfaces or substrates that at least partially include ruthenium. The composition includes a synergistic combination of ammonia and oxygenated halogen compound. The composition may further include abrasive and acid(s). A polishing composition for use on ruthenium materials may include ammonia, present in an amount of 0.01 wt % to 10 wt %, based on the total weight of the composition; hydrogen periodate, present in an amount of 0.01 wt % to 10 wt %, based on the total weight of the composition; silica, present in an amount of 0.01 wt % to 12 wt %, based on the total weight of the composition; and organic sulfonic add, present in an amount of 0.01 wt % to 10 wt %, based on the total weight of the composition, wherein the pH of the composition is between 6 and 8.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional PatentApplication 62/649,326, filed on Mar. 28, 2018, which is hereinincorporated by reference.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

The present disclosure provides a chemical mechanical polishing (CMP)composition that is advantageous for polishing ruthenium materials at ahigh rate. In particular, the CMP compositions of the present disclosurecomprise, in part, a synergistic combination of ammonia and anoxygenated halogen compound, which may also be a perhalogenate compoundor a halogen peroxy acid.

2. Description of the Related Art

In back-end-of-line (BEOL) applications in the semiconductor industry,ruthenium is one of the next generation interconnect materials, becauseof its superior filing capability and good conductivity. Unlike someother materials, such as cobalt, ruthenium is relatively chemicallystable and thus does not deteriorate. It also has favorable depositionproperties. However, ruthenium can be difficult to remove during a CMPprocess. Accordingly, there is a need for a CMP composition that removesruthenium at sufficiently high rates.

SUMMARY OF THE DISCLOSURE

In one embodiment, the present disclosure provides a CMP compositionthat comprises a synergistic combination of ammonia and oxygenatedhalogen compound. The composition may also comprise abrasives, acids,and other stabilizers and removal rate enhancers.

In another aspect, embodiments disclosed herein relate to polishingcompositions for use on ruthenium, including ammonia; an oxygenatedhalogen compound; an abrasive; and optionally, an acid; wherein the pHof the composition is between about 5 and about 10. The presentdisclosure also provides a method of removing ruthenium material from asubstrate, comprising the step of applying the above-identifiedcomposition to the substrate while polishing the substrate with arotating polishing pad.

In yet another aspect, embodiments disclosed herein relate to polishingcompositions for use on ruthenium materials, including ammonia, presentin an amount of about 0.01 wt % to about 10 wt %, based on the totalweight of the composition; hydrogen periodate, present in an amount ofabout 0.01 wt % to about 10 wt %, based on the total weight of thecomposition; silica, present in an amount of about 0.01 wt % to about 12wt %, based on the total weight of the composition; and organic sulfonicacid, present in an amount of about 0.01 wt % to about 10 wt %, based onthe total weight of the composition, wherein the pH of the compositionis between about 6 and about 8.

In yet another aspect, embodiments disclosed herein relate to polishingslurry concentrates for use on ruthenium materials, including: a Rusurface passivation layer softener; a removal rate enhancer; anabrasive; and a Ru oxidizer; wherein the pH of the composition isbetween about 6 and 8.

DETAILED DESCRIPTION OF THE DISCLOSURE

The CMP compositions of the present disclosure address the problem ofpolishing and removing ruthenium material at a satisfactorily high ratefrom a layered semiconductor device. The CMP compositions of the presentdisclosure comprise a synergistic combination of ammonia and oxygenatedhalogen compound, for example periodate. Throughout this applicationammonia may also be referred to as ammonium hydroxide, which is the formthat ammonia takes when dissolved in an aqueous solution, such as theCMP compositions of the present disclosure. The combination issynergistic since, as discussed in greater detail below, the rutheniumremoval rate of a composition including both of these ingredients is fargreater that what one would expect based on the ruthenium removal ratesof compositions containing each component alone.

Without being bound by theory, it is believed that the presentcombination of ammonia and the oxygenated halogen compound is soadvantageous because the oxygenated halogen first oxidizes rutheniumeasily. The ammonia can then easily complex with ruthenium oxide. Oneexample of this ammonium-ruthenium oxide complex can have the followingstructure and formula:

The oxygenated halogen compound of the present disclosure serves as anoxidizer for ruthenium. When the ruthenium oxide is formed, andcomplexed with ammonia, it can be removed by mechanical action of theabrasive. The halogen can be any from the known group, such as but notlimited to iodine, bromine, or chlorine. In one embodiment, theoxygenated halogen compound is hydrogen periodate, which has thechemical formula HIO₄ (meta form) or H₅IO₆ (ortho form). Other suitablecompounds include hydrogen bromate, or hydrogen chlorate. The oxygenatedhalogen compound can be present in an amount of 0.01 wt % to 10 wt %,based on the total weight of the composition, or any subrangestherebetween. The oxygenated halogen compound can also be present in anamount of 0.01 wt % to 2 wt %, based on the total weight of thecomposition, or any subranges therebetween.

As discussed above, ammonia can react or complex with the rutheniumoxide formed after reaction with the oxygenated halogen compound.Ammonia can be present in an amount of 0.01 wt % to 10 wt %, based onthe total weight of the composition, or any subranges therebetween.Ammonia can also be present in an amount of 0.01 wt % to 1 wt %, basedon the total weight of the composition, or any subranges therebetween.

The present disclosure contemplates that other hydroxide compounds maybe used in place of ammonia/ammonium hydroxide, though as discussedbelow they may not work as well. In particular, potassium hydroxide maystill work well enough with the oxygenated halogen compound of thepresent disclosure to produce a sufficiently high ruthenium removalrate.

The composition of the present disclosure also includes abrasives. Theabrasives can be selected from the group consisting of alumina, silica,titania, ceria, zirconia, co-formed products thereof, or mixturesthereof. The abrasive can be present in an amount of 0.01 wt % to 12 wt%, based on the total weight of the composition, or any subrangestherebetween. The abrasive can also be present in an amount of 0.01 wt %to 6 wt %, based on the total weight of the composition, or anysubranges therebetween.

The composition of the present disclosure also includes acids, whichserve as removal rate enhancers or surfactants for roughness surfacecontrol of ruthenium. The acids of the present disclosure can beselected from the group consisting of carboxylic acids, organic sulfonicacids, organic phosphonic acids, or any combinations thereof. Examplesof organic sulfonic acids include 1,2-ethanedisulfonic acid,4-amino-3-hydroxy-1-naphthalenesulfonic add,8-hydroxyquinoline-5-sulfonic add, aminomethanesulfonic acid,benzenesulfonic acid, hydroxylamine O-sulfonic acid, methanesulfonicacid, m-xylene-4-sulfonic acid, poly(4-styrenesulfonic acid),polyanetholesulfonic add, P-toluenesulfonic add, andtrifluoromethane-sulfonic acid. Examples of organic phosphonic acidsinclude poly(vinylphosphonic acid), 1-hydroxyethane-1,1-diphosphonicacid, nitrilotri(methylphosphonic acid), diethylenetriaminepentakis(methylphosphonic acid), N,N,N′,N′-ethylenediaminetetrakis(methylenephosphonic acid), n-hexylphosphonic acid, benzylphosphonic acid andphenylphosphonic acid. The acid can be present in an amount of 0.01 wt %to 10 wt %, based on the total weight of the composition, or anysubranges therebetween. The acid can also be present in an amount of0.01 wt % to 1 wt %, based on the total weight of the composition, orany subranges therebetween.

The pH of the composition should be set in a slightly acidic to neutralto slightly alkaline range, as this leads to a higher removal rate ofruthenium. Thus, the pH can be from 5 to 10, or any subrangestherebetween, or from 6 to 8, or any subranges therebetween.

In one optional embodiment, the compositions of the present disclosureare substantially free of azoles, such as benzotriazole and itsderivatives. As used in the present disclosure, “substantially free of”can mean 10 ppm or less, or 5 ppm or less, or 1 ppm or less. In anotherembodiment, the compositions of the present disclosure do not includeany azole compounds.

The composition of the present disclosure is summarized in the followingtable:

TABLE 1 Broad Range, wt % Component Function Ammonia/Ammonium 0.01 to 10Counter ion, Ru surface Hydroxide passivation layer softener Acid 0.01to 10 Removal rate enhancer or polymer surfactant for Ru surfaceroughness control Abrasive 0.01 to 12 Abrasive Oxygenated halogen 0.01to 10 Ru Oxidizer

In one or more embodiments, the compositions of the present disclosuremay include less than 1%, or less than 0.1% by weight of otheradditives/components not listed in Table 1 and described previously inthe present application with respect to each component. In one or moreembodiments, the compositions of the present disclosure consist of onlythe components listed in Table 1 and described previously in the presentapplication with respect to each component, and water. For example, insome embodiments, the compositions of the present disclosure mayspecifically exclude one or more of the following additive components,or any combinations thereof. Such components are selected from the groupconsisting of polymers having a molecular weight of greater than 250g/mol or greater than 500 g/mol, or greater than 1000 g/mol, or in someembodiments greater than 2000 g/mol, oxygen scavengers, quaternaryammonium salts (including quaternary ammonium hydroxides such as TMAH),amines, alkali bases such as KOH, NaOH and LiOH, surfactants other thana defoamer, a defoamer, fluoride containing compounds, silicates,hydroxycarboxylic acids containing more than two hydroxyl groups,carboxylic and polycarboxylic acids lacking amino groups, silanes (e.g.,alkoxysilanes), cyclic compounds (e.g., azoles (such as diazoles,triazoles, or tetrazoles), triazines, and cyclic compounds containing atleast two rings, such as substituted or unsubstituted naphthalenes, orsubstituted or unsubstituted biphenylethers), buffering agents,non-azole corrosion inhibitors, and metal salts (e.g., metal halides).

EXAMPLES

Examples are provided to further illustrate the capabilities of thepolishing compositions and methods of the present disclosure. Theprovided examples are not intended and should not be construed to limitthe scope of the present disclosure.

For all examples, an Applied Materials Mirra CMP polisher was used witha downforce of 1.5 psi and a flow rate of 1.75 mL/min to polish SKW CVDRu wafers.

Table 1a below shows removal rate data for titanium, ruthenium, andtetra-ethyl-ortho-silicate (TEOS), for several example compositions ofthe present disclosure. Two different types of ruthenium layers weretested, namely those applied with a physical vapor deposition (PVD) anda chemical vapor deposition (CVD).

TABLE 1a EX1 EX2 EX3 NH₃ (% wt, net) 0.1797 0.0449 0.1797 Organicsulfonic acid (% wt, net) 0.1 0.05 0.1 Abrasive (% wt, net solids) 2 0.50.5 H₅IO₆ (% wt, net) 1.5 0.38 1.5 pH 6.85 7.32 6.75 PVD Ru RR (A/min):2700 516 2352 CVD Ru RR (A/min): 2460 624 2724 Ti RR (A/min) 101 20 34TEOS RR (A/min) 188 41 58

EX2 is a 4× dilution of EX 1. EX3 is the same composition as EX1, withthe amount of silica abrasive reduced to 0.5 wt %. As can be seen, eachof EX1-EX3 have high ruthenium removal rates and low Ti and TEOS removalrates. Importantly, the compositions of the present disclosure removeruthenium applied via PVD and CVD equally well.

Table 1b shows removal rate data for several additional compositions ofthe present disclosure, where the amount of ammonia and periodate arevaried.

TABLE 1b EX4 EX5 EX6 EX7 NH₃ (% wt, net) 0.040 0.100 0.140 0.180 Organicsulfonic acid 0.03 0.03 0.03 0.03 (% wt, net) Abrasive (% wt, netsolids) 0.50 0.50 0.50 0.50 H₅IO₆ (% wt, net) 0.38 0.80 1.20 1.50 pH 7.07.0 7.0 7.0 CVD Ru RR (A/min): 636 1356 2028 2604

As can be seen in Table 1b, when the amount of ammonia and periodate areincreased, the ruthenium removal rate can be very high.

Table 2 below shows a sample composition of the present disclosure,wherein ammonia is compared to other compounds in the hydroxide family.

TABLE 2 EX8 CE1 EX9 CE2 CE3 NH₃ (% wt, net) 0.04 NaOH (% wt, net) 0.09KOH (% wt, net) 0.08 Tetramethylammonia- 0.19 hydroxide (% wt, net)Monoethanolamine (% wt, 0.20 net) Organic sulfonic acid 0.03 0.03 0.030.03 0.03 (% wt, net) Abrasive (% wt, net solids) 0.50 0.50 0.50 0.500.50 H₅IO₆ (% wt, net) 0.38 0.38 0.38 0.38 0.38 pH 6.5 6.5 6.5 6.5 6.5CVD Ru RR (A/min): 722 274 522 318 48

EX8, EX9, and CE1-CE3 are the same with the exception of the ammonia andhydroxide compounds used. The wt. % of the ammonia and hydroxidecompounds used in these compositions varies so as to keep the pHconstant. As can be very clearly seen, even at very low amounts ofammonia, EX8 of the present disclosure provides a very high removal rateof ruthenium. CE1-CE3 contain higher amounts of hydroxides, and providemuch lower ruthenium removal rates. This improved result is due to thebeneficial and unexpected effects of how ammonia, the oxygenated halogencompound, and ruthenium work together in the manner described above. InEX9, potassium hydroxide is used. As is also discussed above, while notas effective as ammonia, potassium hydroxide may exhibit sufficientlyhigh removal rates of ruthenium to be used in ammonia's stead.

Table 3a shows data where the ammonia of the present disclosure isreplaced with sodium hydroxide, and the amount of periodate is varied.

TABLE 3a CE4 CE5 CE6 CE7 NH₃ (% wt, net) NaOH (%) 0.085 0.171 0.2640.370 Organic sulfonic acid (% wt, 0.025 0.025 0.025 0.025 net) Abrasive(% wt, net solids) 0.50 0.50 0.50 0.50 H₅IO₆ (% wt, net) 0.40 0.80 1.201.60 POU pH 7.0 7.0 7.0 7.0 CVD Ru RR (A/min): 260 644 896 1936

Table 3a shows that increasing the amount of periodate can increase theremoval rate of ruthenium. However, CE7, EX3 (from Table 1a), and EX7(from Table 1b) have a similar amount of periodate, in fact CE7 hasslightly more the other two (1.60 wt % to 1.5 wt %). The rutheniumremoval rate of CE7 is only 1936 Angstroms/min for CVD. By contrast, theCVD ruthenium removal rate for EX3 is 2724 Angstroms/min, and the CVDruthenium removal rate for EX7 is 2604 Angstroms/min. The maindifference between the two compositions is the amount of ammonia in EX3and EX7. This is a clear indication that ammonia improves the rutheniumremoval rate of periodate significantly.

Table 3b illustrates concept this even more clearly. In Table 3b, theamount of ammonia is varied, while the periodate is replaced withpropionic acid, a compound that is a metal oxidizer in CMP compositions.

TABLE 3b CE8 CE9 CE10 CE11 NH₃ (% wt, net) 0.045 0.090 0.135 0.180 NaOH(%) Organic sulfonic acid (% wt, 0.025 0.025 0.025 0.025 net) Abrasive(% wt, net solids) 0.50 0.50 0.50 0.50 H₅IO₆ (% wt, net) PA (% wt, net)0.168 0.342 0.515 0.679 POU pH 7.0 7.0 7.0 7.0 CVD Ru RR (A/min): 0 0 00

As is clearly shown, ammonia itself has no ability to remove rutheniumwithout periodate or the other oxygenated halogen compounds of thepresent disclosure. This is true even when the amount of ammonia isincreased. Since ammonia has no ability to remove ruthenium on its own,the fact that it would boost the ability of oxygenated halogen compoundto remove ruthenium so significantly was completely unexpected.

Table 4 shows the effect of using other oxidizers than the oxygenatedhalogen compound of the present disclosure.

TABLE 4 CE12 CE13 EX10 NH₃ (% wt, net) 0.05 0.05 0.05 H₂O₂ (% wt, net)0.50 NaClO (% wt, net) 0.25 H₅IO₆ (% wt, net) 0.38 SiO₂ (% wt, net) 0.500.50 0.50 pH 7.0 7.0 7.0 CVD Ru RR (A/min): 58 235 659

CE12 (hydrogen peroxide) and CE13 (sodium chlorate) exhibitsignificantly lower ruthenium removal rates than EX10, which is acomposition according to the present disclosure.

Table 5 shows the effect of pH on the compositions of the presentdisclosure.

TABLE 5 EX11 EX12 EX13 CE14 CE15 NH₃ (% wt, net) 0.03 0.04 0.05 0.070.09 Organic sulfonic acid 0.03 0.03 0.03 0.03 0.03 (% wt, net) Abrasive(% wt, net 0.50 0.50 0.50 0.50 0.50 solids) H₅IO₆ (% wt, net) 0.38 0.380.38 0.38 0.38 pH 6 6.5 8 8.5 9 CVD Ru RR (A/min) 756 822 522 444 336 TiRR (A/min) 25 26 33 35 39 TEOS RR (A/min) 40 39 33 33 33

As can be seen in Table 5, the composition of the present disclosureshows very high removal rates for ruthenium compared to Ti or TEOS inslightly acidic, neutral, or slightly alkaline environments. When the pHbecomes too highly alkaline, the removal rate can suffer.

While the present disclosure has been described with reference to one ormore exemplary embodiments, it will be understood by those skilled inthe art that various changes may be made and equivalents may besubstituted for elements thereof without departing from the scope of thepresent disclosure. In addition, many modifications may be made to adapta particular situation or material to the teachings of the disclosurewithout departing from the scope thereof. Therefore, it is intended thatthe present disclosure not be limited to the particular embodiment(s)disclosed as the best mode contemplated, but that the disclosure willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A ruthenium polishing composition, comprising:ammonia, present in an amount of about 0.03 wt % to about 0.05 wt %,based on the total weight of the composition; an oxygenated halogencompound, present in an amount of about 0.01 wt % to about 10 wt %,based on the total weight of the composition, wherein the oxygenatedhalogen compound comprises a halogen selected from the group consistingof iodine, bromine, chlorine, and any combinations thereof; an abrasive;water; optionally, an acid; and less than about 1 wt % of any additionalcomponents, wherein the pH of the polishing composition is between about6 and about 8, wherein the composition excludes tetra methyl ammoniumhydroxide, and wherein, at a downforce of 1.5 psi and a flow rate of 175mL/min, the composition polishes CVD ruthenium and tetraethyl orthosilicate (TEOS) at a selectivity ratio of ruthenium to TEOS that is15.82 or greater.
 2. The composition of claim 1, wherein the oxygenatedhalogen compound is hydrogen periodate.
 3. The composition of claim 1,wherein the abrasive is selected from the group consisting of alumina,silica, titania, ceria, zirconia, co-formed products thereof, and anycombinations thereof.
 4. The composition of claim 1, wherein theabrasive is silica.
 5. The composition of claim 1, wherein the abrasiveis present in an amount of about 0.01 wt % to about 12 wt %, based onthe total weight of the composition.
 6. The composition of claim 1,wherein the abrasive is present in an amount of about 0.01 wt % to about6 wt %, based on the total weight of the composition.
 7. The compositionof claim 1, wherein the acid is selected from the group consisting of acarboxylic acid, an organic sulfonic acid, an organic phosphonic acid,or any combinations thereof.
 8. The composition of claim 1, wherein theacid is selected from the group consisting of 1,2-ethanedisulfonic acid,4-amino-3-hydroxy-1-naphthalenesulfonic acid,8-hydroxyquinoline-5-sulfonic acid, aminomethanesulfonic acid,benzenesulfonic acid, hydroxylamine O-sulfonic acid, methanesulfonicacid, m-xylene-4-sulfonic acid, poly(4-styrenesulfonic acid),polyanetholesulfonic acid, P-toluenesulfonic acid, andtrifluoromethane-sulfonic acid, poly(vinylphosphonic acid),1-hydroxyethane-1,1-diphosphonic acid, nitrilotri(methylphosphonicacid), diethylenetriaminepentakis (methylphosphonic acid),N,N,N′N′-ethylenediaminetetrakis(methylene phosphonic acid),n-hexylphosphonic acid, benzylphosphonic acid, phenylphosphonic acid,and any combinations thereof.
 9. The composition of claim 1, wherein theacid is present in an amount of about 0.01 wt % to about 10 wt %, basedon the total weight of the composition.
 10. The composition of claim 1,wherein the acid is present in an amount of about 0.01 wt % to about 1wt %, based on the total weight of the composition.
 11. The compositionof claim 1, wherein the composition is substantially free of azoles. 12.The composition of claim 1, wherein the composition consists of theammonia, the oxygenated halogen compound, the abrasive, the water, andoptionally the acid.
 13. The polishing composition of claim 1, whereinthe abrasive is silica, present in an amount of about 0.01 wt % to about12 wt %, based on the total weight of the composition, and wherein theacid is an organic sulfonic add present in an amount of about 0.01 wt %to about 10 wt %, based on the total weight of the composition.
 14. Amethod of removing ruthenium material from a substrate, comprising thestep of applying the composition of claim 1 to the substrate whilepolishing the substrate with a rotating polishing pad.
 15. A rutheniumpolishing composition, comprising: a ruthenium surface passivation layersoftener comprising ammonia in an amount of about 0.03 wt % to about0.05 wt %; a removal rate enhancer; an abrasive; a ruthenium oxidizercomprising hydrogen periodate; water; and less than about 1 wt % of anyadditional components, wherein the pH of the composition is betweenabout 6 and
 8. 16. A ruthenium polishing composition, comprising:ammonia, present in an amount of about 0.03 wt % to about 0.05 wt %;hydrogen periodate, present in an amount of about 0.01 wt % to about 10wt %, based on the total weight of the composition; an abrasive; anacid; water; and less than about 1 wt % of any additional components,wherein the pH of the polishing composition is between about 7 and about8.
 17. The composition of claim 16, wherein the acid is selected fromthe group consisting of a carboxylic acid, an organic sulfonic acid, anorganic phosphonic acid, or any combinations thereof.
 18. Thecomposition of claim 16, wherein the acid is selected from the groupconsisting of 1,2-ethanedisulfonic acid,4-amino-3-hydroxy-1-naphthalenesulfonic acid,8-hydroxyquinoline-5-sulfonic acid, aminomethanesulfonic acid,benzenesulfonic acid, hydroxylamine O-sulfonic acid, methanesulfonicacid, m-xylene-4-sulfonic acid, poly(4-styrenesulfonic acid),polyanetholesulfonic acid, P-toluenesulfonic acid, andtrifluoromethane-sulfonic acid, poly(vinylphosphonic acid),1-hydroxyethane-1,1-diphosphonic acid, nitrilotri(methylphosphonicacid), diethylenetriaminepentakis (methylphosphonic acid),N,N,N′N′-ethylenediaminetetrakis(methylene phosphonic acid),n-hexylphosphonic acid, benzylphosphonic acid, phenylphosphonic acid,and any combinations thereof.
 19. The composition of claim 16, whereinthe acid is present in an amount of about 0.01 wt % to about 10 wt %,based on the total weight of the composition.
 20. The composition ofclaim 16, wherein the acid is present in an amount of about 0.01 wt % toabout 1 wt %, based on the total weight of the composition.